CN101779047B

CN101779047B - Fluid bearing device

Info

Publication number: CN101779047B
Application number: CN200880102673.0A
Authority: CN
Inventors: 平出淳; 尾藤仁彦; 山本哲也
Original assignee: NTN Corp
Current assignee: NTN Corp
Priority date: 2007-08-20
Filing date: 2008-08-12
Publication date: 2014-07-02
Anticipated expiration: 2028-08-12
Also published as: US20100202715A1; US8297844B2; CN101779047A

Abstract

Intended is to make it possible to manufacture a highly precise and strong shaft member at a low cost. The shaft member (2) includes a shaft portion (21) and a flange portion (22) disposed at one end of the shaft portion (21). The flange portion (22) is formed into an annular shape, and the shaft portion (21) and the flange portion (22) are fixed by a welded portion (23), which is formed by irradiating the upper end of the inner circumference with a laser (35).

Description

Hydrodynamic bearing device

Technical field

The present invention relates to hydrodynamic bearing device.

Background technique

Hydrodynamic bearing device is that to utilize the oil film that is formed at bearing play be rotation bearing means freely by shaft component supporting.This FDB has the features such as High Rotation Speed, high running accuracy, low noise, effectively utilize in recent years its feature, be applicable to being used as and be equipped on the bearing means of using with the motor of the various electric equipment headed by information equipment, more particularly, as disk sets such as HDD, the optical disk unit such as CD-ROM, CD-R/RW, DVD-ROM/RAM, the spindle drive motor of the magneto-optical disc apparatus such as MD, MO etc., the polygon mirror scanner motor of laser printer (LBP), the colour wheel motor of projector, the motor bearing means of fan motor etc.

For example, the hydrodynamic bearing device that spindle drive motor is used possesses: bearing sleeve; Insert the interior week of bearing sleeve, and carry out counterrotating shaft component with respect to bearing sleeve.As shaft component, use the member in one end of axial region with lip part more, in this case, between the outer circumferential face of axial region and the inner peripheral surface of bearing sleeve, be formed with radial bearing gap, for example, between at least one party's of lip part end face and face (, the end face of bearing sleeve) corresponding thereto, be formed with thrust-bearing gap.As this flanged shaft component, have by machinings such as cuttings and be integrally formed the one type of axial region and lip part and by suitable mechanism, axial region and the lip part made respectively carried out to integrated split type.

Flanged shaft component of one type can be guaranteed high fastening strength between axial region and lip part, needs but then special process equipment in the time that it is made, and cost significantly uprises.Therefore, recently, there is the situation that flanged shaft component is formed as to split type.

There are various situations as flanged shaft component of split type is known, as the shaft component that can guarantee high fastening strength between axial region and lip part, for example No. 3774080 communique of Japan Patent (patent documentation 1) recorded, known have by welding axial region and lip part are carried out to integrated structure.And, in TOHKEMY 2004-340368 communique (patent documentation 2), disclose in welding and especially by resistance welding, axial region and lip part are carried out to integrated structure.

Patent documentation 1: No. 3774080 communique of Japan Patent

Patent documentation 2: TOHKEMY 2004-340368 communique

As shown in above-mentioned patent documentation 1, if axial region and lip part are welded, can guarantee high fastening strength at the two.But, for example, making that one end of axial region and circular lip part are chimeric, while welding this embedding part, the melts such as the metal particle producing while having welding disperse and are attached to the outer circumferential face of axial region of face or the misgivings of the end face of lip part that become a side who forms bearing play.And, because weld part is formed on the position adjacent with bearing play, therefore need its shape to pay special consideration.Although described problem can, by weld job being thought to various ways or being implemented afterwards other fine finishing in welding and solve, can produce the surging problem of processing cost.

On the other hand, the disclosed flanged shaft component of above-mentioned patent documentation 2 is provided with small circular protrusion and the recess adjacent with projection the either party of the end face of mutually relative axial region and lip part, auxiliary voltage under the state that the front end of projection is contacted with the opposing party and make projection melting, thus, axial region and lip part are welded and fixed.If this structure, the melt of projection is housed in recess, therefore can eliminate the problems referred to above.And, owing to can preventing that described melt from entering between the axial region in outside and the bearing surface of lip part of weld part, therefore can improve assembly precision.But, in order to guarantee desirable precision (coaxality or squareness etc.) and fastening strength between axial region and lip part, must form accurately circular protrusion, and the two the attitude in when assembling management accurately, thereby the problem that cannot avoid processing cost surging had.For example, although can guarantee the coaxality between the two by utilizing the attitude of fixture restriction axial region and lip part, but in the inadequate situation of squareness between end face and the outer circumferential face of for example axial region, because axial region contacts with lip part point, therefore be difficult to spread all over complete cycle and guarantee uniform weld strength, thereby have the misgivings of fastening strength deficiency required between axial region and lip part.

Summary of the invention

The present invention is in view of above problem, and its problem is, can low cost provide a kind of highi degree of accuracy and high-intensity flanged shaft component.

As the first structure for solving above-mentioned problem, in the present invention, provide a kind of hydrodynamic bearing device, it possesses: the shaft component in one end of axial region with lip part; The radial bearing gap being formed by the outer circumferential face of axial region; The thrust-bearing gap being formed by the end face of lip part, described hydrodynamic bearing device is characterised in that, lip part is circular, has the weld part that lip part and axial region are welded and fixed in its axial region side one end week.

As mentioned above, because week in the axial region side one end that is formed as circular lip part has the weld part that axial region and lip part are welded and fixed, therefore can effectively suppress to weld time, the melt such as the metal particle of generation disperses and is attached to the situation of the outer circumferential face of axial region or the end face of lip part.And because weld part is formed on interior week of circular lip part, therefore it forms form and the precision of bearing play is not exerted an influence.Therefore, need not think various ways to weld job, also need not implement other fine finishing, just can manufacture highi degree of accuracy and high-intensity flanged shaft component.

As mentioned above, for example, make that one end of axial region and circular lip part are chimeric carries out welded structure afterwards to the embedding part of the two if be formed as, the squareness of the axial region after welding and lip part depends on the machining accuracy of chimeric surface (being pressed into face).Therefore, when axial region and lip part are fixed to (welding), the outer circumferential face that not only becomes the axial region of a side's who forms radial bearing gap face needs highi degree of accuracy processing in advance, and the inner peripheral surface of lip part also needs highi degree of accuracy processing in advance, thereby causes the increase of processing cost.Therefore in the present invention, provide the structure that forms weld part under a kind of state of the end contact the two end face of axial region and lip part is contacted.If be formed as described structure,, owing to managing the squareness between axial region and lip part by the fixture that when welding is used, therefore can produce at low cost high-precision shaft component in batches, thereby preferably.

In above-mentioned the first structure, be provided with aligning face at axial region, and the inner circumference edge portion that makes this aligning face and lip part (strictly speaking, the inner circumference edge portion of axial region side one end) butt, but also can be provided with aligning face in the inner circumference edge portion of lip part (the inner circumference edge portion of axial region side one end), and make axial region and this aligning face butt.In described structure, because lip part can be shaken the head with respect to axial region, therefore can be more easily and highi degree of accuracy carry out the centering of the two.In addition, as the form of aligning face, can enumerate towards the other side's side member conical surface or convex surface of undergauge gradually.

Above-described weld part can form by the laser that irradiates in interior week to lip part.Conventionally, because the external diameter of lip part is 5～10mm left and right, internal diameter is 1～2mm left and right, therefore in other welding method, is difficult to form accurately weld part, if but laser bonding, small weld part also can highi degree of accuracy form.

In addition, weld part can form by the projection irradiation laser of the axial region side one end to the inner peripheral surface that is arranged on lip part.So, due to the fusion range circumscribed of lip part inner peripheral surface, therefore the heat affecting to lip part can be suppressed, for inferior limit, can effectively prevent its distortion.Therefore, can omit with the fine finishing after the welding that is deformed into cause of lip part, thereby preferably.

Weld part can spread all over complete cycle and form on the circumferencial direction in the interior week of lip part, also can on the circumferencial direction in the interior week of lip part, be interrupted formation.If be formed as the former structure,, compared with the latter's structure, the advantage that has the fastening strength of the two to improve, if be formed as the latter's structure, compared with the former structure, there is the advantage of the distortion possibility of the lip part that the heat affecting can reduce with welding time accompanies.

In addition, as the second structure for solving above-mentioned problem, in the present invention, provide a kind of hydrodynamic bearing device, it possesses: the shaft component in one end of axial region with lip part; The radial bearing gap being formed by the outer circumferential face of axial region; The thrust-bearing gap being formed by the end face of lip part, described hydrodynamic bearing device is characterised in that, axial region is soldered fixing with the state that is folded with core-regulating mechanism and the two line is contacted between the two with lip part.In addition,, at this, so-called core-regulating mechanism is the mechanism of the relation that can shake the head with respect to the opposing party of the either party that realizes axial region and lip part.

So, if axial region is soldered fixing with the state that is folded with core-regulating mechanism and the two line is contacted between the two with lip part, the either party of axial region and lip part can shake the head with respect to the opposing party, therefore only limit the relative attitude of axial region and lip part by assembling fixture, just can carry out the aligning of axial region and lip part and highi degree of accuracy is carried out the centering between the two.,, owing to can relaxing respectively axial region and the desired machining accuracy of lip part, therefore can make low processing cost.And now, weld owing to contacting at the two line under the state of preferred ring-type contact, therefore can improve weld strength.

In addition, as welding method, although can use resistance welding, more preferably laser bonding.Resistance welding is connected to that area of contact between soldered member is less and therefore tendency that weld strength is higher, in the structure of the present invention being welded and fixed, can have superiority at axial region with lip part line under the state contacting aspect weld strength.And in resistance welding, the formation material of axial region and lip part is restricted to conductive metal, if but laser bonding, without considering the strong and weak of electric conductivity or having or not, even and if then also can guarantee each other high weld strength at different metal.Therefore, need not consider the weldability of axial region and lip part, and can form as the most applicable material of the required quality of shaft component by meeting.

As the concrete structure of above-mentioned core-regulating mechanism, there are the core-regulating mechanism with aligning face and recess, described aligning face is formed on the either party of axial region and lip part, and towards the member undergauge of the opposing party's side; Described recess is arranged at the opposing party's member, and accommodates the front end of aligning face.Core-regulating mechanism can consist of setting other member different from axial region or lip part, but can make cost increase due to other member being set, therefore not preferred.With regard to this aspect, as mentioned above, if form core-regulating mechanism by being formed on either party's the aligning face of axial region and lip part and the recess that is arranged on the opposing party, can prevent that described cost from increasing, thus preferred.

Above-mentioned aligning face can be formed by the conical surface or convex surface.In the time considering the workability (processing cost) of aligning face, aligning face is that the conical surface is more favourable.On the other hand, as mentioned above, in the present invention, so-called core-regulating mechanism is the mechanism of the relation that can shake the head with respect to the opposing party of the either party that realizes axial region and lip part, that is, be the mechanism that not only can revise the centering of axial region and lip part and can revise the squareness between the two.Therefore,, if consider described item, to be formed as convex surface more favourable for aligning face.Specifically, when aligning face is formed as to convex surface, no matter the inner circumference edge of recess is formed as to which kind of shape, can both guarantees the line contact condition of axial region and lip part, and carry out the two centering and squareness correction simultaneously.On the other hand, when aligning face is formed as to the conical surface, guarantee the line contact condition of axial region and lip part if want, and realize the two centering and squareness correction simultaneously, need the inner circumference edge of recess to be formed as convex surface (R face).From above situation, aligning face is formed as to the conical surface or convex surface, be not only to consider the workability of aligning face and the mono-Decision of Jian that carries out is fixed, but the formation material etc. of considering axial region and lip part is the processing cost of shaft component entirety etc. and can selecting arbitrarily.

In second structure of the invention described above, axial region and lip part can be welded and fixed in the inside of recess.So, if the two is welded and fixed in the inside of recess, the heat affecting while welding is difficult to involve the outer circumferential face of the axial region that forms bearing play or the end face of lip part, thus the situation that can do one's utmost to avoid the surface accuracy etc. of described each to worsen.And weld mark is outstanding is formed on the periphery of axial region or one end of lip part, thus the situation that can effectively avoid bearing performance involved by bad influence.And then, in the time that the two is carried out to laser bonding, be accompanied by the irradiation of laser, there is melt to disperse and be attached to the misgivings of the end face of lip part, if but the two is welded in the inside of recess, can cover welding part by recess, therefore can reduce the possibility of end face (thrust bearing surface) that melt is attached to lip part etc.

Because hydrodynamic bearing device of the present invention has above feature, therefore can be suitable for packing into the motor with stator coil and rotor magnet and for example coil the spindle drive motor that device uses and use.

As implied above, according to the present invention, can manufacture at low cost highi degree of accuracy and high-intensity flanged shaft component.Thus, can provide at low cost a kind of hydrodynamic bearing device that can the high running accuracy of long term maintenance.

Brief description of the drawings

Fig. 1 is the sectional drawing of an example of the schematically illustrated information equipment spindle drive motor that packs hydrodynamic bearing device into.

Fig. 2 is the sectional drawing that the first mode of execution of the hydrodynamic bearing device that has been suitable for the first structure of the present invention is shown.

Fig. 3 A is the sectional drawing of the bearing sleeve shown in Fig. 2.

Fig. 3 B is the figure that the downside end face of the bearing sleeve shown in Fig. 2 is shown.

Fig. 4 is the sectional drawing of the manufacturing process of the shaft component shown in schematically illustrated Fig. 2.

Fig. 5 is the sectional drawing of the manufacturing process of the shaft component shown in schematically illustrated Fig. 2.

Fig. 6 A is the major component amplification profile of Fig. 5.

Fig. 6 B is the major component amplification profile of the shaft component after weld part forms.

The major component amplification profile of Fig. 5 when Fig. 7 A is the lip part that has used other structure.

The major component amplification profile of the shaft component after weld part when Fig. 7 B is the lip part having used shown in Fig. 7 A forms.

Fig. 8 is the sectional drawing that the second mode of execution of the hydrodynamic bearing device that has been suitable for the first structure of the present invention is shown.

Fig. 9 is the sectional drawing that the 3rd mode of execution of the hydrodynamic bearing device that has been suitable for the first structure of the present invention is shown.

Figure 10 is the sectional drawing that the 4th mode of execution of the hydrodynamic bearing device that has been suitable for the first structure of the present invention is shown.

Figure 11 is the major component amplification profile that the variation of the hydrodynamic bearing device shown in Figure 10 is shown.

Figure 12 is the sectional drawing that the 5th mode of execution of the hydrodynamic bearing device that has been suitable for the first structure of the present invention is shown.

Figure 13 is the sectional drawing that the first mode of execution of the hydrodynamic bearing device that has been suitable for the second structure of the present invention is shown.

Figure 14 A is the sectional drawing of the bearing sleeve shown in Figure 13.

Figure 14 B is the figure that the downside end face of the bearing sleeve shown in Figure 13 is shown.

Figure 15 A is the sectional drawing of the manufacturing process of the shaft component shown in schematically illustrated Figure 13.

Figure 15 B is the sectional drawing of the manufacturing process of the shaft component shown in schematically illustrated Figure 13.

Figure 16 A is the major component amplification profile of the variation of the shaft component shown in schematically illustrated Figure 13.

Figure 16 B is the major component amplification profile of the variation of the shaft component shown in schematically illustrated Figure 13.

Figure 16 C is the major component amplification profile of the variation of the shaft component shown in schematically illustrated Figure 13.

Figure 16 D is the major component amplification profile of the variation of the shaft component shown in schematically illustrated Figure 13.

Figure 17 is the sectional drawing that the second mode of execution of the hydrodynamic bearing device that has been suitable for the second structure of the present invention is shown.

Figure 18 is the sectional drawing that the 3rd mode of execution of the hydrodynamic bearing device that has been suitable for the second structure of the present invention is shown.

Figure 19 is another routine major component amplification profile that the shaft component shown in Figure 13 is shown.

Label declaration:

1 hydrodynamic bearing device

2 shaft components

7 housings

8 bearing sleeves

21 axial regions

21c lower end surface

22 lip parts

22a upside end face

22c inner peripheral surface

22d projection

23 weld parts

24 aligning faces

35 laser

A radial bearing surface

B, C thrust bearing surface

R1, R2 radial bearing portion

T1, T2 thrust bearing division

101 hydrodynamic bearing devices

102 shaft components

111 core-regulating mechanisms

112 aligning faces

113 recesses

114 weld parts

121 axial regions

122 lip parts

131 first fixtures

132 second fixtures

133 laser

A11 radial bearing surface

B11, C11 thrust bearing surface

R11, R12 radial bearing portion

T11, T12 thrust bearing division

Embodiment

Below, based on brief description of the drawings embodiments of the present invention.

The schematically illustrated information equipment that packs hydrodynamic bearing device into of Fig. 1 one structure example of spindle drive motor.This spindle drive motor is used in the disk drive devices such as HDD, and it possesses: shaft component 2 is supported as rotation hydrodynamic bearing device 1 freely; Be installed on the hub 3 of shaft component 2; Across for example gap radially and relative stator coil 4a and rotor magnet 4b; Support 5.Stator coil 4a is arranged on the periphery of support 5, and rotor magnet 4b is arranged on the interior week of hub 3.The housing 7 of hydrodynamic bearing device 1 is arranged on the interior week of support 5.Maintain one or the dish such as multiple (illustrated example is two) disks 6 in hub 3.If to stator coil 4a energising, utilize the electromagnetic force between stator coil 4a and rotor magnet 4b to make rotor magnet 4b rotation, thus, hub 3 and dish 6 and shaft component 2 one rotations.

Fig. 2 illustrates the first mode of execution of the hydrodynamic bearing device 1 that has been suitable for the first structure of the present invention.Hydrodynamic bearing device 1 shown in this figure possesses: housing 7; Be fixed on the bearing sleeve 8 in the interior week of housing 7; Insert the shaft component 2 in the interior week of bearing sleeve 8; The lid member 9 that one end opening of housing 7 is sealed; The sealing component 10 that the other end opening of housing 7 is sealed.In addition, for convenience of explanation, taking sealing component 10 sides as upside, taking the axial opposed side contrary with it as downside, carry out following explanation.

Housing 7 is formed as cylindric by the metallic material such as brass or resin material.By such as bonding, be pressed into, the suitable method such as deposited and bearing sleeve 8 being fixed on the inner peripheral surface 7a of housing 7.Be formed with the lid member stationary plane 7b than the large footpath of inner peripheral surface 7a in the lower end side of inner peripheral surface 7a.

Bearing sleeve 8 is formed as cylindric by for example porous plastid of the sintering metal taking copper as main component.Bearing sleeve 8 can or not be other porous plastid (for example, Porous resin) formation of sintering metal by soft metal materials such as such as brass except sintering metal yet.

As shown in Figure 3A, at the inner peripheral surface 8a of bearing sleeve 8, separate upper and lower two places and be formed with multiple dynamic pressure groove 8a1,8a2 are arranged in to cylindrical region that chevron shape forms as radial dynamic pressure generating unit.In the present embodiment, the dynamic pressure groove 8a1 of upside is formed as axially asymmetric with respect to axial centre m (the axial central authorities in region between upper and lower tipper), larger than the axial dimension X2 of underside area by the axial dimension X1 of upper-side area than axial centre m.On the other hand, the dynamic pressure groove 8a2 of downside is formed as axial symmetry, and the axial dimension in its upper and lower region equates with above-mentioned axial dimension X2 respectively.In addition, dynamic pressure groove can be formed on the radial bearing surface A of following axial region 21, and its shape also can be formed as known other shapes such as spiral-shaped.

As shown in Figure 3 B, be formed with multiple dynamic pressure groove 8b1 are arranged in to spiral-shaped annular section as thrust dynamic pressure generating unit at the downside end face 8b of bearing sleeve 8.In addition, dynamic pressure groove (thrust dynamic pressure generating unit) also can be formed on the thrust bearing surface B of following lip part 22, and its shape also can be formed as known other shapes such as chevron shape.

On the outer circumferential face 8c of bearing sleeve 8, be formed with one or more axial groove 8c1 to both ends of the surface opening.And, on the upside end face 8d of bearing sleeve 8, be formed with annular groove 8d1 and one or more radial groove 8d2 being connected with the internal side diameter of annular groove 8d1.

Lid member 9 is formed as discoid by for example metallic material or resin material, and is fixed on the lid member stationary plane 7b of housing 7 by proper methods such as boning, be pressed into.Although not shown, on the upside end face 9a of this lid member 9, be formed with the annular section that multiple dynamic pressure grooves are arranged in to spiral-shaped or chevron shape as thrust dynamic pressure generating unit.Dynamic pressure groove also can be formed on the thrust bearing surface C of following lip part 22.

Sealing component 10 is formed as circular by the soft metal materials such as such as brass or other metallic material or resin material, and is fixed on the upper end portion of the inner peripheral surface 7a of housing 7 by suitable methods such as boning, be pressed into.Between the inner peripheral surface 10a of sealing member 10 and the outer circumferential face 21a of axial region 21, form by the seal space S specifying.Seal space S has the pooling feature that the volume-variation amount to accompanying with the temperature variation of lubricant oil that is full of hydrodynamic bearing device 1 absorbs, and in the scope of imaginary temperature variation, the pasta of lubricant oil is always in the scope in seal space S.Outside diameter at the downside end face 10b of sealing component 10 is formed with one or more radial groove 10b1.

Shaft component 2 comprises axial region 21 and from the lower end of axial region 21 to the side-prominent lip part 22 of external diameter.Axial region 21 is by the metallic material of high rigidity in the present embodiment for stainless steel is formed as solid shaft, and lip part 22 is formed as circular equally by stainless steel.Details is as described below, and lip part 22 is welded and fixed with respect to axial region 21 by forming the weld part 23 in week in all formation in the top more strictly speaking therein.At the outer circumferential face 21a of axial region 21, separate in the axial direction two places and be formed with that to become level and smooth cylinder planar and form region diametrically opposed radial bearing surface A, A with the dynamic pressure groove 8a1, the 8a2 that are arranged on the inner peripheral surface 8a of bearing sleeve 8.Between two radial bearing surface A, A, be formed with the 21b of non-contact portion than radial bearing surface A path.

On the upside end face 22a of lip part 22, be provided with and be arranged on dynamic pressure groove 8b1 on the downside end face 8b of bearing sleeve 8 and form region relative thrust bearing surface B in thrust direction, and, on downside end face 22b, be provided with and be arranged on dynamic pressure groove on the upside end face 9a that covers member 9 and form region relative thrust bearing surface C in thrust direction.Two thrust bearing surface B, C are the level and smooth tabular surface that there is no dynamic pressure groove etc.

Hydrodynamic bearing device 1 is made up of above member, also comprises in the internal porosity of bearing sleeve 8 and be all full of lubricant oil in the inner space of the housing 7 that utilizes sealing component 10 to seal.And, now, in the space being formed by the inner peripheral surface 22c of lip part 22 and the lower end surface 21c of axial region 21, be also full of lubricant oil.

In the hydrodynamic bearing device 1 being made up of above structure, if shaft component 2 rotates, dynamic pressure groove 8a1, the 8a2 of bearing sleeve 8 form between region and radial bearing surface A, the A of axial region 21 and are formed with radial bearing gap.And, follow the rotation of shaft component 2, its oil film rigidity raises due to the dynamic pressure effect of dynamic pressure groove 8a1,8a 2 to be formed on oil film in radial bearing gap, utilize this pressure and by shaft component 2 non-contact diametrically supporting for rotation freely.Thus, separation axis is formed with to two places shaft component 2 non-contact diametrically supporting for rotating the R1 of radial bearing portion, R2 freely.

In addition, meanwhile, between thrust bearing surface B, the C of lip part 22 and the upside end face 9a of the downside end face 8b of bearing sleeve 8 and lid member 9, be formed with respectively thrust-bearing gap.And, follow the rotation of shaft component 2, be formed on oil film its oil film rigidity rising due to the dynamic pressure effect of dynamic pressure groove in two thrust-bearing gaps, be to rotate freely due to this pressure by shaft component 2 non-contact supporting in two thrust directions.Thus, being formed with shaft component 2 non-contact supporting in two thrust directions is rotation the first thrust bearing division T1 and the second thrust bearing division T2 freely.

In addition, in the time that shaft component 2 rotates, as mentioned above, because seal space S is the diminishing cone-shaped of private side towards housing 7, the direction that therefore lubricant oil in seal space S is narrowed to seal space due to the draw of capillary force generation is drawn to the private side of housing 7.Thus, can effectively prevent that lubricant oil from spilling from the inside of housing 7.

In addition, as mentioned above, the dynamic pressure groove 8a1 of upside is formed as axially asymmetric with respect to axial centre m, larger than the axial dimension X2 of underside area by the axial dimension X1 of upper-side area than axial centre m.Therefore, in the time that shaft component 2 rotates, the tractive force of the lubricant oil being produced by dynamic pressure groove 8a1 (suction force) in upper-side area than the relative increase of underside area.And, due to the differential pressure of this tractive force, and the lubricant oil being filled in the gap between the inner peripheral surface 8a of bearing sleeve 8 and the outer circumferential face 21a of axial region 21 flows downwards, in the path of the fluid passage of the fluid passage of the fluid passage in gap between the downside end face 8b of bearing sleeve 8 and the upside end face 22a of lip part 22 → formed by the axial groove 8c1 of bearing sleeve 8 → formed by the radial groove 10b1 of sealing component 10 → formed by annular groove 8d1 and the radial groove 8d2 of bearing sleeve 8, circulate, be again drawn in the radial bearing gap of the first R1 of radial bearing portion.

So, make lubricant oil flow circuit in the inner space of housing 7 by being configured to, can, in the pressure balanced while that keeps lubricant oil, can eliminate the problem such as the leakage of lubricant oil or the generation of vibration that the generation of the bubble accompanying with the generation of local negative pressure and the generation of bubble cause.Because seal space S is communicated with above-mentioned circulating path, even the in the situation that of therefore in thereby bubble former because of some are sneaked into lubricant oil, also can be in the time following lubrication oil circulation bubble be discharged to extraneous gas from the pasta (gas-liquid interface) of the lubricant oil in seal space S.Therefore, can further effectively prevent the bad influence by Bubble formation.

Below, describe the manufacture method of above-mentioned shaft component 2 in detail.

Fig. 4～Fig. 6 is the manufacturing process that above-mentioned shaft component 2 is shown, in more detail, is that the major component amplification profile that axial region 21 and lip part 22 is carried out to the operation of laser bonding is shown.The major component of the manufacturing installation shown in Fig. 4 and Fig. 5 comprises: be fixed on the bed die 31 on base station by such as bolt etc.; Be configured in the top of bed die 31, and be set to intermediate mold 32 and the upper die tooling 33 that can relatively move with respect to bed die 31 by suitable driving mechanism; Irradiate the not shown laser irradiation device of laser 35.Dispose the axle support member 34 that the upper-end surface 21d of axial region 21 is supported and the resilient member 36 being formed by elastomers such as springs interior week at bed die 31, axle support member 34 is by utilizing its lower end of resilient member 36 yielding supports, and can be with respect to bed die 31 relative sliding vertically.Axle support member 34 has the 34a of Ngok portion stretching out to outside diameter in lower end, under state at the each mould 31～33 shown in Fig. 4 in origin position, by the 34a of Ngok portion is engaged in the axial direction with the ladder surface 31c of the below that is arranged on bed die 31, limit displacement upward.

Bed die 31 has the retaining hole 31a that keeps axial region 21.The degree that retaining hole 31a is set as making axial region 21 not rock and make radial bearing surface A not to be damaged, the internal diameter size that in other words axial region 21 is set as being gently pressed into degree.Under the state shown in Fig. 4, the axial dimension of retaining hole 31a (span between the upper-end surface 31b of bed die 31 and the upper-end surface of axle support member 34) is set as shortening than the total length size of axial region 21 size of established amount.Therefore, as shown in Figure 4, if axial region 21 is inserted to retaining hole 31a, axial region 21 is subject to radial constraint and its lower end surface 21c than the upper-end surface 31b of bed die 31 outstanding established amount upward.

Intermediate mold 32 is formed as circular, by utilizing the outer circumferential face of inner circumferential surface 32a limit flange portion 22, carrys out moving radially of limit flange portion 22.

Upper die tooling 33 has and cooperates with the upper-end surface 31b of bed die 31 and the restriction face 33a of the both ends of the surface of limit flange portion 22 and become the through hole 33b of the entrance port of laser 35.At this, from Fig. 5 clearly, the width of restriction face 33a is set as than the reduced width established amount of the downside end face 22b of lip part 22.If press whole of the downside end face 22b of lip part 22 by the restriction face 33a of upper die tooling 33, the downside end face 22b of lip part 22 imitates the restriction face 33a of upper die tooling 33, the misgivings that have the fixed precision of axial region 21 and lip part 22 to worsen.

But, in this flanged shaft component, affect significantly bearing performance with respect to the squareness of the upside end face 22a (thrust bearing surface B) of the lip part 22 of the outer circumferential face 21a (radial bearing surface A) of axial region 21.Therefore,, in order to ensure the squareness of the regulation between described bearing surface, need fully raising with respect to the squareness of the upper-end surface 31b of the retaining hole 31a (internal face) of bed die 31.

Laser irradiation device can use the known various lasers such as YAG laser, carbon dioxide laser, semiconductor laser, fiber optics laser.Wherein, if consider beam quality or Economy and then consideration weld strength or the easy weldability etc. of the laser 35 irradiating, preferred YAG laser or carbon dioxide laser.As the radiation modality of laser 35, can be continous way or pulsed either type.

In addition, although not shown, can between for example laser irradiation device and upper die tooling 33, configure and there is the concavees lens of the beam diameter for regulating laser 35 or the beam diameter controlling mechanism of convex lens.Although not shown equally, near the situation that prevents from being oxidized weld part 23 in weld job, and preferred disposition ejection is used for the shielding gas injection apparatus of the non-active gas such as argon gas or nitrogen that cuts off surrounding atmosphere.

In the device being formed by above structure, first, as shown in Figure 4, axial region 21 is inserted in the retaining hole 31a of bed die 31.Next, as shown in Figure 5, by lip part 22 be positioned in the lower end surface 21c of axial region 21 upper after, upper die tooling 33 moved downwards and make the restriction face 33a of upper die tooling 33 and the downside end face 22b butt of lip part 22.And then, if upper die tooling 33 is moved, and make the upside end face 22a of lip part 22 and the lower end surface 21c butt of axial region 21 downwards, carry out both ends of the surface 22a, the 22b of limit flange portion 22 by the restriction face 33a of upper die tooling 33 and the upper-end surface 31b of bed die 31.Now, because resilient member 36 produces compressive strain, thereby the lower end surface 21c of axial region 21 is with the upside end face 22a butt of suitable oppressive force and lip part 22.In addition, as mentioned above, owing to guaranteeing to have the squareness of regulation between the inner peripheral surface at bed die 31 (internal face of retaining hole 31a) and upper-end surface 31b, therefore can fully improve the precision of the lower end surface 21c of axial region 21 and the upside end face 22a of lip part 22, thereby in the moment of the upside end face 22a of lip part 22 and the lower end surface 21c butt of axial region 21, between the radial bearing surface A of axial region 21 and the thrust bearing surface B of lip part 22, can guarantee the squareness of regulation.

Carry out side by side (or after restriction) of both ends of the

surface

22a, 22b of limit flange portion 22 with the restriction face 33a of upper-end surface 31b by bed die 31 and upper die tooling 33, the outer circumferential face of the inner peripheral surface 32a limit flange portion 22 by intermediate mold 32.Thus, lip part 22 is with respect to both sides axially and radially, its mobile restricted system.In addition,, after limit flange portion 22, each mould 31～33, by utilizing such as not shown fixing bolt etc. fixing together, cannot move in welding.

Then,, as shown in Fig. 5 and Fig. 6 A, never illustrated laser irradiation device irradiates laser 35 so that laser 35 passes through the through hole 33b of upper die tooling 33 and the hole of lip part 22 to week in the upper end of lip part 22.If irradiate laser 35 by described mode, lower end melting, the joint of week and the axial region 21 being adjacent in the upper end of lip part 22, as shown in Figure 6B, the lower end surface 21c that lip part 22 is weldingly fixed on to axial region 21 above forms weld part 23.In addition, in the present embodiment, by irradiating continuously in a circumferential direction laser 35, and the interior all complete cycles that spread all over lip part 22 are formed with weld part 23.

Then, form after the weld part 23 of regulation, if make upper die tooling 33 and intermediate mold 32 reset to initial point, and take out axial region 21 from the retaining hole 31a of bed die 31, can obtain the conduct shown in Fig. 2 and complete the shaft component 2 of product.

As implied above, if week forms the weld part 23 that axial region 21 and lip part 22 are fixed in the upper end that is formed as circular lip part 22, the melt such as metal particle producing can prevent from welding reliably time disperses and is attached to the situation of the outer circumferential face 21a (radial bearing surface A) of axial region 21 or the upside end face 22a (thrust bearing surface B) of lip part 22, described outer circumferential face 21a becomes a side's who forms radial bearing gap face, and described upside end face 22a becomes a side's in the thrust-bearing gap that forms the first thrust bearing division T1 face.And, can prevent as much as possible that the situation of the downside end face 22b (thrust bearing surface C) that is attached to lip part 22, described downside end face 22b from becoming a side's in the thrust-bearing gap that forms the second thrust bearing division T2 face.And because weld part 23 is formed on interior week of lip part 22, therefore it forms form the precision in bearing play (radial bearing gap and thrust-bearing gap) is not exerted an influence.Therefore, after welding, need not implement other fine finishing, and can manufacture at low cost highi degree of accuracy and high-intensity shaft component 2.

As mentioned above, lip part 22 is formed as when circular, after making one end of axial region 21 and the interior week of lip part 22 chimeric, also can welding the embedding part of the two.But if be formed as described structure, the squareness of the axial region 21 after welding and lip part 22 depends on the machining accuracy of chimeric surface (the outer circumferential face 21a of axial region 21 and the inner peripheral surface 22c of lip part 22).Therefore, need in advance the outer circumferential face 21a of fine finishing axial region 21 and the inner peripheral surface 22c of lip part 22 accurately, thereby cause the increase of processing cost.On the other hand, if as in the present invention, under the state of the end contact that the end face 21c of axial region 21 and the upside end face 22a of lip part 22 are contacted, the two is welded, can manage the squareness between axial region 21 and lip part 22 by each mould 31～33 that when welding is used, therefore can suppress the increase of processing cost.

In addition, although be fixed with hub 3 (with reference to Fig. 1) in the upper end of axial region 21 in the time of assembling motor, if but now the fastening strength between axial region 21 and lip part 22 is insufficient, the misgivings that have axial region 21 to separate with lip part 22 due to the plus-pressure of hub 3 when fixing.For interior week of the lower end by making axial region 21 and lip part 22 is chimeric and the embedding part of the two is carried out to welded structure and avoid this bad situation, need to form weld part at the two end part in the hole of lip part 22, thereby weld job is bothersome.On the other hand, if as in the present invention, under the state (with the axial state engaging) that axial region 21 and lip part 22 is carried out to end contact, weld, the plus-pressure when the lower end surface 21c of axial region 21 is engaged in the axial direction resist hub 3 fixing with the upside end face 22a of lip part 22.Therefore, weld part 23 only forms just enough at an axial place, therefore from this point, can suppress the increase of processing cost.

In addition, if make axial region 21 chimeric with the interior week of lip part 22, need to make the total length Size growth of axial region 21, thereby cause the increase of material cost or the weight of shaft component 2 of shaft component 2.On the other hand, if as in the present invention, under the state that axial region 21 and lip part 22 is carried out to end contact, weld, both made the total length that shortens axial region 21 also can guarantee the total length size required as shaft component 2.Therefore, can realize reduction and the lightweight of the material cost of shaft component 2, thereby can contribute to the high running accuracy of hydrodynamic bearing device 1 or high-speed rotary to transform.

In addition, because weld part 23 forms by irradiating laser 35, therefore can form accurately small weld part 23.Especially in the present embodiment, owing to forming weld part 23 by irradiating laser 35 under the state of the both ends of the surface 22a in

limit flange portion

22,22b, therefore can effectively prevent due to follow laser 35 irradiation heat affecting and produce at lip part 22 situation that warpage etc. is out of shape.

In the present embodiment, although form axial region 21 and lip part 22 both sides by stainless steel, if laser bonding also can be guaranteed high fastening strength between different metal.Therefore, require characteristic (intensity etc.), just difference mutually of the formation material of axial region 21 and lip part 22 as long as can meet with respect to shaft component 2.For example, can form axial region 21 by stainless steel, and form lip part 23 by brass etc.

In addition, in the above-described embodiment, although form the structure of weld part 23 for spreading all over the interior all complete cycles of lip part 22, as long as can guarantee the fastening strength of regulation between axial region 21 and lip part 22, just form weld part 23 without spreading all over complete cycle, and can be interrupted in a circumferential direction formation.So, can further reduce the distortion possibility of the lip part 22 that the heat affecting while irradiation by laser 35 causes.

Above, illustrated and used internal diameter size to spread all over the structure that total length is constant lip part 22, but the form of lip part 22 is not limited to above-mentioned situation.For example, as shown in Figure 7 A, also can use upper end portion (ends of axial region 21 sides) at inner peripheral surface 22c to be provided with the lip part 22 of the projection 22d of the ring-type side-prominent to internal diameter.Make under the state of the upside end face 22a of lip part 22 and the lower end surface 21c butt of axial region 21, this projection 22d is made as and the neat face of upside end face 22a of lip part 22, so that the lower end surface 21c butt of its upside end face (end faces of axial region 21 sides) and axial region 21.

While using the lip part 22 of described structure, as shown in Figure 7 A, 7 B, weld part 23 can form by projection 22d is irradiated to laser 35.So, due to the fusion range circumscribed of the inner peripheral surface 22c of lip part 22, therefore the heat affecting to lip part 22 can be suppressed for inferior limit, thereby can more effectively prevent its distortion.

In addition, the size that the size of projection 22d directly affects the weld part 23 of formation is the weld strength between axial region 21 and lip part 22, if the misgivings that have in the time that laser 35 irradiates the melts such as the metal particle that produces disperse to be attached to the mode of downside end face 22b of lip part 22 excessive, have the misgivings that cannot guarantee desirable fastening strength (weld strength) if too small.Therefore, the size of projection 22d suitably setting of quality as requested in the scope that does not produce the problems referred to above.This projection 22d for example with lip part 22 is carried out being integrally formed in Blanking Shaping or forging and molding.

Above, a mode of execution of the hydrodynamic bearing device that is suitable for the first structure of the present invention has been described, but the first structure of the present invention is not limited to above-mentioned hydrodynamic bearing device.Below, although other mode of execution of the hydrodynamic bearing device that is suitable for the first structure of the present invention is described, below, to state above bright structure be the structure of benchmark additional common with reference to label, omit repeat specification.

Fig. 8 is the figure that the second mode of execution of the hydrodynamic bearing device 1 that has used the first structure of the present invention is shown.Hydrodynamic bearing device 1 shown in this figure is with the main difference of Fig. 2, on the downside end face 22b of lip part 22, do not form thrust bearing surface C, and the second thrust bearing division T2 is arranged on the point between the downside end face 3a1 of round plate 3a and the upside end face 7c of housing 7 of the hub 3 of the upper end of being fixed on axial region 21, and seal space S is arranged on the point between the taper outer circumferential face 7d of housing 7 and the inner peripheral surface 3b 1 of the cylindrical part 3b of hub 3.

Fig. 9 is the figure that the 3rd mode of execution of the hydrodynamic bearing device 1 that has been suitable for the first structure of the present invention is shown.In the hydrodynamic bearing device 1 shown in this figure, shaft component 2 also possess be positioned at bearing sleeve 8 above the second lip part 42, and the second thrust bearing division T2 is arranged on the point between the upside end face 8d of the second lip part 42 and bearing sleeve 8, and outer circumferential face 22e, the 42e of two lip parts 22,42 and the inner peripheral surface 7a of housing 7 between form on the point of seal space S, with above-mentioned mode of execution be different structure.So, even if use, two lip parts 22,42 are arranged in the situation of shaft component 2 of axial region 21, also can be suitable for the structure of the invention described above about axial region 21 and the integral piece of lip part 22 of lower end that is arranged on axial region 21.

Figure 10 is the figure that the 4th mode of execution of the hydrodynamic bearing device 1 that has been suitable for the first structure of the present invention is shown, is the variation of the hydrodynamic bearing device 1 shown in Fig. 2.In the hydrodynamic bearing device 1 shown in this figure, the lower end surface 21c of axial region 21 that forms shaft component 2 is formed as the convex surface working as aligning face 24, under the state that this convex surface is engaged with the upper end inner circumference edge portion of lip part 22, by being formed on all weld parts 23 in the upper end of lip part 22, axial region 21 and lip part 22 is fixed.If such structure, lip part 22 can be shaken the head with respect to axial region 21.Therefore, in the time that the manufacturing installation (fixture) by shown in Fig. 4 and Fig. 5 comes limit flange portion 22 with respect to the attitude of axial region 21, the centering of the two can be easily and accurately carried out, highi degree of accuracy and high-intensity shaft component 2 can be more easily manufactured.

In addition, may not leave no choice but the lower end surface 21c entirety of axial region 21 to be formed as convex surface, example as shown in figure 11, also can only be formed on the part engaging with the upper end in the hole of lip part 22.Now, also can form the minor diameter part 21d extending downwards in the lower end of axial region 21.If described structure, can reduce the volume in the space in the interior week that is formed on lip part 22, thereby can reduce the oil mass being full of in the inner space of hydrodynamic bearing device 1.

Figure 12 is the figure that the 5th mode of execution of the hydrodynamic bearing device 1 that has been suitable for the first structure of the present invention is shown, is the variation of the hydrodynamic bearing device 1 shown in Fig. 2.In the hydrodynamic bearing device 1 shown in this figure, the 22e of upper end inner circumference edge portion of lip part 22 is formed as the convex surface working as aligning face 24, under the state of Yu Gai upper end, the lower end 22e of inner circumference edge portion (aligning face 24) butt that makes axial region 21, is formed with weld part 23 at the interior Zhou Shangduan of lip part 22.Even if be formed as in the situation of this spline structure, also identical with the mode of execution shown in Figure 10 and Figure 11, lip part 22 can be shaken the head with respect to axial region 21, therefore come the attitude of limit flange portion 22 with respect to axial region 21 at the manufacturing installation (fixture) by shown in Fig. 4 and Fig. 5, the centering of the two can be easily and accurately carried out, thereby highi degree of accuracy and high-intensity shaft component 2 can be more easily manufactured.

The aligning face 24 of axial region 21 or lip part 22 that is arranged on except being formed by convex surface, also can by the member towards the other side's side gradually the conical surface of undergauge form.And so, the structure that aligning face 24 is set at axial region 21 or lip part 22 can be applicable to the hydrodynamic bearing device 1 shown in Fig. 8 and Fig. 9 (shaft component 2) certainly.And then, certainly can be welded and fixed thering is the lip part 22 of projection 22d week in the upper end shown in Fig. 7 A with respect to the aligning face 24 of axial region 21 (more than, entirely not shown).

Figure 13 is the figure that the first mode of execution of the hydrodynamic bearing device 101 that has been suitable for the second structure of the present invention is shown.Hydrodynamic bearing device 101 shown in this figure possesses: bearing sleeve 108; Insert the shaft component 102 in the interior week of bearing sleeve 108; Bearing sleeve 108 and shaft component 102 are housed in to the housing 107 in interior week; The lid member 109 that one end opening of housing 107 is sealed; The sealing component 110 that the other end opening of housing 107 is sealed.In addition, for convenience of explanation, taking sealing component 110 sides as upside, taking its axial opposed side as downside, carry out following explanation.

Housing 107 is formed as cylindric by the metallic material such as brass or resin material.The inner peripheral surface of housing 107 is divided into the path inner peripheral surface 107a of relative path and the large footpath inner peripheral surface 107b in relative large footpath in the axial direction, on path inner peripheral surface 107a, be fixed with bearing sleeve 108 by suitable methods such as for example boning, be pressed into, be deposited respectively, on large footpath inner peripheral surface 107b, be fixed with and cover member 109.

Bearing sleeve 108 is formed as cylindric by for example porous plastid of the sintering metal taking copper as main component.Bearing sleeve 108 also can for example, be formed by the porous plastid (Porous resin) outside the soft metal materials such as such as brass or sintering metal except sintering metal.

As shown in Figure 14 A, at the inner peripheral surface 108a of bearing sleeve 108, separate upper and lower two places and be formed with the region that multiple dynamic pressure groove 108a1,108a2 are arranged in to chevron shape as radial dynamic pressure generating unit.In the present embodiment, the dynamic pressure groove 108a1 of upside is formed as axially asymmetric with respect to axial centre m (the axial central authorities in region between upper and lower tipper), larger than the axial dimension X12 of underside area by the axial dimension X11 of upper-side area than axial centre m.On the other hand, the dynamic pressure groove 108a2 of downside is formed as axial symmetry, and the axial dimension in its upper and lower region equates with above-mentioned axial dimension X12 respectively.In addition, dynamic pressure groove can be formed on the radial bearing surface A11 of following axial region 121, and its shape also can be formed as known other shapes such as spiral-shaped.

As shown in Figure 14B, on the downside end face 108b of bearing sleeve 108, be formed with multiple dynamic pressure groove 108b1 are arranged in to spiral-shaped annular section as thrust dynamic pressure generating unit.In addition, dynamic pressure groove (thrust dynamic pressure generating unit) can be formed on the thrust bearing surface B11 of following lip part 122, and its shape also can be formed as known other shapes such as chevron shape.

On the outer circumferential face 108c of bearing sleeve 108, be formed with one or more axial groove 108c1 to both ends of the surface opening.And, on the upside end face 108d of bearing sleeve 108, be formed with one or more annular groove 108d1 and the radial groove 108d2 being connected with the internal side diameter of annular groove 108d1.

Lid member 109 is formed as discoid by for example metallic material or resin material.Although not shown, on the upside end face 109a of this lid member 109, be formed with the annular section that multiple dynamic pressure grooves are arranged in to spiral-shaped or chevron shape as thrust dynamic pressure generating unit.Dynamic pressure groove also can be formed on the thrust bearing surface C11 of following lip part 122.

Sealing component 110 is formed as ring-type by the soft metal materials such as such as brass or other metallic material or resin material, and is fixed on the upper end portion of the inner peripheral surface 107a of housing 107 by suitable methods such as boning, be pressed into.Between the inner peripheral surface 110a of sealing member 110 and the outer circumferential face 121a of axial region 121, be formed with the seal space S11 of regulation.Seal space S11 has the pooling feature that the volume-variation amount to accompanying with the temperature variation of lubricant oil that is filled in hydrodynamic bearing device 101 absorbs, and in the scope of imaginary temperature variation, the pasta of lubricant oil is always in the scope in seal space S11.

Shaft component 102 comprises the lip part 122 that axial region 121 and the outside diameter to axial region 121 stretch out, and at this, the two is all formed by stainless steel by metallic material for axial region 121 and lip part 122 both sides.On the outer circumferential face 121a of axial region 121, separate in the axial direction two places and be formed with that to become level and smooth cylinder planar and form region diametrically opposed radial bearing surface A11, A11 with the dynamic pressure groove 108a1, the 108a2 that are arranged on the inner peripheral surface 108a of bearing sleeve 108.Between two radial bearing surface A11, A11, be formed with the 121b of non-contact portion than radial bearing surface A11 path.

On the upside end face 122a of lip part 122, be provided with and be arranged on dynamic pressure groove 108b1 on the downside end face 108b of bearing sleeve 108 and form region relative thrust bearing surface B11 in thrust direction, and, on downside end face 122b, be provided with and be arranged on dynamic pressure groove on the upside end face 109a that covers member 109 and form region relative thrust bearing surface C11 in thrust direction.Two thrust bearing surface B11, C11 are formed as the level and smooth tabular surface without dynamic pressure groove etc.

Axial region 121 is soldered fixing with the state that is folded with core-regulating mechanism 111 and the two line is contacted between the two with lip part 122.In the present embodiment, core-regulating mechanism 111 comprises: towards lip part 122 sides (downside) the aligning face 112 of the convex surface shape of undergauge (spherical shape) gradually of lower end that is formed on axial region 121; Be formed at lip part 122, and accommodate the recess 113 of the front end of the aligning face 112 of axial region 121.In addition, in the present embodiment, recess 113 becomes to the through hole of the both ends of the surface 122a of lip part 122,122b opening, and axial region 121 and lip part 122 are welded and fixed by the weld part 114 of inside of the recess 113 that is formed on lip part 122.The manufacture method of this shaft component 102 is described in detail below.

Hydrodynamic bearing device 101, by forming with upper member, is all full of lubricant oil in the internal porosity that in the inner space of the housing 107 that utilizes sealing component 110 to seal, also comprises bearing sleeve 108.

In the hydrodynamic bearing device 101 being formed by above structure, if shaft component 102 rotates, form between region and radial bearing surface A11, the A11 of axial region 121 and be formed with radial bearing gap at dynamic pressure groove 108a1, the 108a2 of bearing sleeve 108.And, follow the rotation of shaft component 102, its oil film rigidity raises due to the dynamic pressure effect of dynamic pressure groove 108a1,108a2 to be formed on oil film in radial bearing gap, utilize this pressure and by shaft component 102 non-contact diametrically supporting for rotation freely.Thus, separation axis is formed with to two places shaft component 102 non-contact diametrically supporting for rotating the R11 of radial bearing portion, R12 freely.

In addition, meanwhile, between thrust bearing surface B11, the C11 of lip part 122 and the upside end face 109a of the downside end face 108b of bearing sleeve 108 and lid member 109, be formed with respectively thrust-bearing gap.And, follow the rotation of shaft component 102, its oil film rigidity raises due to the dynamic pressure effect of dynamic pressure groove to be formed on oil film in two thrust-bearing gaps, utilize this pressure and by shaft component 102 in two thrust directions non-contact supporting for rotation freely.Thus, being formed with shaft component 102 non-contact supporting in two thrust directions is rotation the first thrust bearing division T11 and the second thrust bearing division T12 freely.

In addition, in the time that shaft component 102 rotates, as mentioned above, because seal space S11 is the diminishing cone-shaped of private side towards housing 107, therefore the lubricant oil in seal space S11 utilizes the draw that capillary force produces, and the direction being narrowed to seal space is drawn to the private side of housing 107.Thus, can effectively prevent that lubricant oil from spilling from the inside of housing 107.

In addition, as mentioned above, the dynamic pressure groove 108a1 of upside is formed as axially asymmetric with respect to axial centre m, larger than the axial dimension X12 of underside area by the axial dimension X11 of upper-side area than axial centre m.Therefore,, in the time that shaft component 102 rotates, the tractive force of the lubricant oil being produced by dynamic pressure groove 108a1 (suction force) is relatively larger than underside area in upper-side area.And, due to the differential pressure of this tractive force, and the lubricant oil being filled in the gap between the inner peripheral surface 108a of bearing sleeve 108 and the outer circumferential face 121a of axial region 121 flows downwards, and circulate in the path of the fluid passage of the fluid passage of the fluid passage in gap between the upside end face 122a of the downside end face 108b by bearing sleeve 108 and lip part 122 → formed by the axial groove 108c1 of bearing sleeve 108 → formed by the radial groove 110b1 of sealing component 110 → formed by annular groove 108d1 and the radial groove 108d2 of bearing sleeve 108, and be again drawn in the radial bearing gap of the first R11 of radial bearing portion.

So, make lubricant oil flow circuit in the inner space of housing 107 by being configured to, in the pressure balanced while that keeps lubricant oil, can eliminate the problem such as generation and the leakage of the lubricant oil that Bubble formation causes or the generation of vibration of the bubble accompanying with the generation of locality negative pressure.Because seal space S11 is communicated with above-mentioned circulating path, even therefore because some reason bubble is sneaked in the situation in lubricant oil, also can be in the time following lubrication oil circulation, the pasta of the lubricant oil by bubble in seal space S11 (gas-liquid interface) is discharged to extraneous gas.Therefore, can more effectively prevent the bad influence that brought by bubble.

Next, describe the manufacture method of above-mentioned shaft component 102 in detail based on Figure 15.

The manufacturing process of Figure 15 A, the schematically illustrated shaft component 102 of Figure 15 B.Assembling device shown in this figure mainly comprises: the first fixture 131; The second fixture 132 with the first fixture 131 arranged coaxial; Irradiate the not shown laser irradiation device of laser 133 from the top of the second fixture 132.The first fixture 131 and the second fixture 132 can move axially relatively due to not shown driving mechanism, and in the present embodiment, the first fixture 131 is fixed side, and the second fixture 132 is drawer at movable side.

The first fixture 131 has the retaining hole 131a that can allow axial region 121 insert and the axial region 121 inserting is kept.The second fixture 132 has: the minor diameter part 132a that makes downside end face 122b (thrust bearing surface C11) butt of lower end surface 132a2 and lip part 122; Lip part 122 is housed in to the large-diameter portion 132b in interior week.Laser irradiation device can use the known lasers such as YAG laser, carbon dioxide laser, semiconductor laser, fiber optics laser, if but consider the beam quality of laser 133 that irradiates or Economy, and and then consider weld strength or easy weldability etc., preferably YAG laser or carbon dioxide laser.As the radiation modality of laser 133, continous way or pulsed can.

In addition, although not shown, between laser irradiation device and the second fixture 132, can be configured for the beam diameter controlling mechanism of beam diameter that regulates laser 133.By described beam diameter controlling mechanism being set, can easily regulating the formation scope etc. that form weld part 114.Although not shown equally, near the situation that prevents from being oxidized the forming portion of weld part 114, also can configure the shielding gas injection apparatus that sprays the non-active gas such as argon gas or nitrogen for cutting off ambient air in weld job.

But, in this flanged shaft component, affect bearing performance with respect to the thrust bearing surface B11 of the lip part 122 of the radial bearing surface A11 of axial region 121, the squareness of C11.Therefore, in order to ensure the squareness of the regulation between described bearing surface, preferably fully improve in advance with respect to the squareness of the minor diameter part lower end surface 132a2 of the second fixture 132 of the inner peripheral surface of the retaining hole 131a of the first fixture 131 and with respect to the parallelism of the minor diameter part lower end surface 132a2 of the second fixture 132 of the upper-end surface 131b of the first fixture 131 etc.

In above structure, first as shown in Figure 15 A, axial region 121 is inserted after the retaining hole 131a of the first fixture 131, lip part 122 is loaded in axial region 121 (on aligning face 112) so that the front end of the aligning face 112 that is arranged at axial region 121 is housed in recess 113.Because the aligning face 112 that is arranged at axial region 121 is formed as convex surface, if therefore lip part 122 is loaded in axial region 121, the two spreads all over complete cycle and keeps the state of ringed line contact, and lip part 122 can be shaken the head with respect to axial region 121.

Next, as shown in Figure 15 B, make the second fixture 132 approach the first fixture 131, make the lower end surface 132b1 of large-diameter portion 132b and the upper-end surface 131b butt of the first fixture 131 of the second fixture 132.While making the second fixture 132 approach the first fixture 131, if the minor diameter part lower end surface 132a2 of the second fixture 132 and the downside end face 122b of lip part 122 are contacted, lip part 122 shakes on the aligning face 112 of axial region 121, thereby lip part 122 is corrected as regulation attitude with respect to the attitude of axial region 121.As mentioned above, owing to guaranteeing the squareness etc. of regulation between each of first, second fixture 131,132, therefore in moment of the first fixture 131 and the second fixture 132 butts, in the centering of carrying out between axial region 121 and lip part 122, between the radial bearing surface A11 of axial region 121 and thrust bearing surface B11, the C11 of lip part 122, can guarantee the squareness of regulation.

Next, never illustrated laser irradiation device irradiates laser 133 and forms the weld part 114 of ring-type to axial region 121 and the ring-type contacting part of lip part 122 in the mode by week in the minor diameter part 132a of the second fixture 132.Then, stop irradiating laser 133 and the second fixture 132 is reset to after initial point, if take out axial region 121 from the first fixture 131, can obtain the conduct shown in Figure 13 and complete the shaft component 102 of product.

As implied above, in the present embodiment, because core-regulating mechanism 111 is between axial region 121 and lip part 122, lip part 122 can be shaken the head with respect to axial region 121, therefore only by utilizing fixture 131,132 to limit the relative attitude of axial region 121 and lip part 122, just can carry out the aligning of axial region 121 and lip part 122, thereby carry out accurately the centering of the two.And, so, owing to can utilizing fixture 131,132 to limit the relative attitude of the two, therefore under the state that makes the two ringed line contact, can be welded and fixed (weld part 114 can be formed as to ring-type), thereby can improve weld strength.Therefore, can easily manufacture highi degree of accuracy and high-intensity shaft component 102.Especially in the present embodiment, not to use the bond strength due to area of contact difference to produce the resistance welding of difference (unbalanced), but use laser bonding to be welded and fixed the two, therefore can obtain stable weld strength.

In addition, because the aligning face 112 by being arranged at axial region 121 and the recess 113 that is arranged at lip part 122 form core-regulating mechanism 111, the problem that the cost that therefore can effectively prevent from worrying in the time utilizing other member to carry out the two aligning increases.

In addition, in the present embodiment, owing to aligning face 112 being formed as to convex surface (sphere), therefore no matter recess 113 is formed as to which kind of shape, under the state that can make axial region 121 contact online with lip part 122, shakes the head freely.Therefore, if make two fixture 131,132 butts, not only easily guarantee the coaxality between axial region 121 and lip part 122, and easily guarantee the squareness with respect to upper and lower end face 122a, the 122b (thrust bearing surface B11, C11) of the lip part 122 of the outer circumferential face 121a (radial bearing surface A11) of axial region 121.

In addition, because the inside at recess 113 is welded and fixed axial region 121 and lip part 122, the heat affecting therefore can do one's utmost to avoid due to welding time and situation that the surface accuracy of the radial bearing surface A11 of axial region 121 or thrust bearing surface B11, the C11 of lip part 122 worsens.And weld mark is that radial bearing gap or thrust-bearing gap are outstanding to the periphery of axial region 121 or the tip side of lip part 122, thereby can effectively avoid bearing performance to produce bad influence.And then, by irradiate laser 133 form in the structure of present embodiment of weld part 114, although dispersing of the melt that the irradiation of worry and laser 133 is accompanied, if but axial region 121 and lip part 122 are welded in the inside (inside of the upside of lip part 122) of recess 113, can cover welding part by the internal face (inner peripheral surface of lip part 122) by recess 113, therefore can effectively prevent that melt from dispersing and being attached to the situation of end face 122a, the 122b etc. of lip part 122.

In addition, in the present embodiment, although form axial region 121 and lip part 122 by stainless steel of the same race, if laser bonding is difficult to guarantee also can guarantee high weld strength between the different metal of high weld strength in resistance welding.Therefore, as long as can guarantee that the required intensity of shaft component 102 is just passable, so axial region 121 is extensive with the options of the formation material of lip part 122, the most applicable material of the quality that can choice for use meets the requirements, can realize the cost degradation of shaft component 102 from this point.For example, can form axial region 121 by stainless steel, and form lip part 122 by brass etc.

As long as can guarantee centering between axial region 121 and lip part 122 and the squareness between bearing surface, the shape of axial region 121 and lip part 122 just can change arbitrarily.

For example, as shown in Figure 16 A, can also be provided with minor diameter part 121c at axial region 121, this minor diameter part 121c extends and is housed in the interior week of recess 113 (through hole) of lip part 122 downwards from tune core face 112.If described structure, can be formed on by minor diameter part 121c landfill the space in the interior week of lip part 122, therefore, compared with the structure shown in Figure 13, can reduce the oil mass of the lubricant oil that be filled in bearing inside.Therefore, can dwindle the axial dimension of seal space S11 and realize the compactness of hydrodynamic bearing device, or amplify the distance between bearings of the R11 of radial bearing portion, R12 and improve bearing rigidity.

In addition, for example, as shown in Figure 16 B, also the recess 113 that is arranged at lip part 122 can not be formed to through hole and is formed as sagged shape.In this case, axial region 121 and lip part 122 can be welded and fixed by form weld part 114 in the annular gap forming between the aligning face 112 of axial region 121 and the upside end face 22a of lip part 122.

Above, form the situation of core-regulating mechanism 111 although the description of the aligning face 112 by being arranged at axial region 121 and the recess 113 that is arranged at lip part 122, but also can form core-regulating mechanism 111 with the recess 113 that is arranged at axial region 121 by the aligning face 112 that is arranged at lip part 122.Specifically, for example, shown in Figure 16 C, Figure 16 D, by be provided with the tune core face 112 being formed as towards the protruding spherical shape of axial region 121 side undergauges at lip part 122, and be provided with the recess 113 of through hole or sagged shape at axial region 121, can under the state that axial region 121 is contacted with lip part 122 ring-types, be welded and fixed.

In addition, in Figure 13, Figure 16 A and Figure 16 C, although form weld part 114 and axial region 121 and lip part 122 be welded and fixed by the inside at recess 113, but also can with Figure 16 B, Figure 16 D in the same manner, in the annular gap between the lower end surface of axial region 121 and the upside end face 122a of lip part 122, form weld part 114.And, as the object of the further high strength of shaft component 102, can form weld part 114 by the inside at recess 113 and described annular gap both sides, axial region 121 and lip part 122 are welded and fixed.

Above, although the description of the first mode of execution of hydrodynamic bearing device 101 that is suitable for the second structure of the present invention, but the second structure of the present invention is not limited to above-mentioned hydrodynamic bearing device 101.Below, although explanation has been used another mode of execution of hydrodynamic bearing device 101 of the second structure of the present invention, below, to state above bright structure be the structure of benchmark additional common with reference to label, omission repeat specification.

Figure 17 is the figure that the second mode of execution of the hydrodynamic bearing device 101 that has been suitable for the second structure of the present invention is shown.Hydrodynamic bearing device 101 shown in this figure is with the main difference point of Figure 13, on the downside end face 122b of the lip part 122 of shaft component 102, be not formed with thrust bearing surface C11, and the second thrust bearing division T12 is arranged on the point between the downside end face 103a1 of round plate 103a and the upside end face 107c of housing 107 of the hub 103 of the upper end of being fixed on axial region 121, and seal space S11 is arranged on the point between the taper outer circumferential face 107d of housing 107 and the inner peripheral surface 103b1 of the cylindrical part 103b of hub 103.In addition,, in illustrated example, although be formed as having used the structure of the shaft component identical with Figure 13 102, certainly can use the shaft component 102 of the structure shown in Figure 16 A～Figure 16 D.

Figure 18 is the figure that the 3rd mode of execution of the hydrodynamic bearing device 101 that has been suitable for the second structure of the present invention is shown.In the hydrodynamic bearing device shown in this figure, also possesses the second lip part 142 of the axial substantial middle portion that is fixed on axial region 121 at shaft component 102, and the second thrust bearing division T12 is arranged on the point between the upside end face 108d of the second lip part 142 and bearing sleeve 108, and outer circumferential face 122c, the 142c of two lip parts 122,142 and the inner peripheral surface 107a of housing 107 between form on the point of seal space S11, with the mode of execution shown in Figure 13 and Figure 17 be different structure.So, even if use, two lip parts 22,42 are arranged in the situation of shaft component 102 of axial region 121, also can be suitable for second structure of the invention described above about axial region 121 and the integral piece of lip part 122 of lower end that is arranged on axial region 121.Certainly, in the present embodiment, also can use the shaft component 102 shown in Figure 16 A～Figure 16 D.

Above, although the description of having the shaft component 102 of the aligning face 112 that is formed as convex surface shape (spherical shape) and packing the hydrodynamic bearing device 101 of this shaft component 102 into, but aligning face 112 also can be formed as the conical surface shown in Figure 19.In this case, the inner circumference edge of recess 113, strictly speaking, inner circumference edge (in illustrated example, the upper end inner circumference edge of the lip part 122) 113a that at least imports aligning face 112 sides is preferably formed as convex surface (R face).By being formed as described structure, axial region 121 similarly becomes the relation of shaking the head freely with lip part 122 and mode of execution described above, in the time that axial region 121 and lip part 122 are welded, not only can guarantee the coaxality of the two, and can guarantee squareness simultaneously.Described structure also can be suitable for adopting in the arbitrary mode of execution being illustrated above.

In addition, if consider the workability (processing cost) of aligning face 112, be formed as the conical surface compared with aligning face 112 being formed as to convex surface more favourable, but in the time that axial region 121 and lip part 122 are welded and fixed, guarantee the two coaxality and squareness if want simultaneously, need as mentioned above the inner circumference edge 113a of recess 113 to be processed into R face.Processing cost is affected by the institute such as formation material or processing method of axial region 121 and lip part 122, therefore adopts which kind of structure according to using the suitably selections such as material.

The hydrodynamic bearing device 1,101 being more than illustrated is all formed as split part by housing and bearing sleeve, but making to be also suitable for adopting the present invention in the two integrated hydrodynamic bearing device.And, especially in the hydrodynamic bearing device shown in Fig. 2, Figure 10 and Figure 13, and then, also can be by integrated in housing the either party of lid member or sealing component.

In addition, above, as radial bearing portion and thrust bearing division, although exemplified with make lubricant oil produce the structure of dynamic pressure effect by chevron shape or spiral-shaped dynamic pressure groove, but as radial bearing portion, also so-called ladder bearing, many arc bearings or non-positive circular journal bearing be can adopt, as thrust bearing division, so-called ladder bearing or waveform bearing also can be adopted.And, above, exemplified with the structure that radial bearing portion is separated to form at axial two places, but also radial bearing portion can be located to an axial place or more than three places.

In addition, above, although the description of the situation that is formed in the both sides of radial bearing portion that axial two places are separated to form by hydraulic bearing, but also can form by the bearing beyond hydraulic bearing one or both of radial bearing portion.For example, although not shown, can be by the radial bearing surface of shaft component is formed as to round type, and the inner peripheral surface of relative bearing sleeve is formed as to round type inner peripheral surface, form so-called positive circular journal bearing.

Claims

1. a hydrodynamic bearing device, it possesses: have axial region and be arranged on the shaft component of the lip part on the end of an axial side of this axial region; The radial bearing gap being formed by the outer circumferential face of described axial region; The thrust-bearing gap being formed by the end face of described lip part, described hydrodynamic bearing device is characterised in that,

Described lip part is formed as circular, has the axial through hole at the end opening of its axial side and opposite side,

Make to be located at the inner circumference edge portion butt of the aligning face of described axial region and the axial opposite side of described lip part, or make aligning face and described axial region butt in the inner circumference edge portion of the axial opposite side that is arranged on described lip part, thus, under the whole region of outer circumferential face of described axial region and the non-contacting state of inner peripheral surface of described lip part, described axial region is engaged in the axial direction with described lip part

In the end of the axial opposite side of described lip part, there is the weld part that described lip part and described axial region are welded and fixed week.

2. hydrodynamic bearing device according to claim 1, wherein,

Described aligning face is made up of convex surface.

3. hydrodynamic bearing device according to claim 1, wherein,

Described weld part irradiates laser by week in the end of the axial opposite side to described lip part and forms.

4. hydrodynamic bearing device according to claim 1, wherein,

Described weld part forms by the projection on end in the inner peripheral surface that is arranged on described lip part, axial opposite side is irradiated to laser.

5. hydrodynamic bearing device according to claim 1, wherein,

Described weld part is formed as ring-type.

6. hydrodynamic bearing device according to claim 1, wherein,

Described weld part is interrupted formation in a circumferential direction.